RD is uncertain if his amps will remain functional with TQ cables, simple as that. He knows they are fine with NVA cable.There is a previously published list of approved speaker cables that NVA amps could tolerate here, so these exclusions are a newer development which has happened about the same time TQ became so popular. The fact that all the previously approved speaker cables are also no longer approved (according to NVA) may suggest the current production version of the circuit is not so robust as previously. If you value your warranty, you should definately stick to the NVA cables, just as old Naim users were 'advised' to stick to approved equipment. FWIW, I understand TQ to be a low capacitance cable, which used to be the basic benchmark as whether a cable was suitable for use with NVA or not. The suggestion in the site linked to above is to avoid cables with capacitance of over 200pF per metre. However the recent change to "NVA only" could mean that lower capacitance than this is now required.